1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_X86_PTRACE_H 3 #define _ASM_X86_PTRACE_H 4 5 #include <asm/segment.h> 6 #include <asm/page_types.h> 7 #include <uapi/asm/ptrace.h> 8 9 #ifndef __ASSEMBLY__ 10 #ifdef __i386__ 11 12 struct pt_regs { 13 /* 14 * NB: 32-bit x86 CPUs are inconsistent as what happens in the 15 * following cases (where %seg represents a segment register): 16 * 17 * - pushl %seg: some do a 16-bit write and leave the high 18 * bits alone 19 * - movl %seg, [mem]: some do a 16-bit write despite the movl 20 * - IDT entry: some (e.g. 486) will leave the high bits of CS 21 * and (if applicable) SS undefined. 22 * 23 * Fortunately, x86-32 doesn't read the high bits on POP or IRET, 24 * so we can just treat all of the segment registers as 16-bit 25 * values. 26 */ 27 unsigned long bx; 28 unsigned long cx; 29 unsigned long dx; 30 unsigned long si; 31 unsigned long di; 32 unsigned long bp; 33 unsigned long ax; 34 unsigned short ds; 35 unsigned short __dsh; 36 unsigned short es; 37 unsigned short __esh; 38 unsigned short fs; 39 unsigned short __fsh; 40 unsigned short gs; 41 unsigned short __gsh; 42 unsigned long orig_ax; 43 unsigned long ip; 44 unsigned short cs; 45 unsigned short __csh; 46 unsigned long flags; 47 unsigned long sp; 48 unsigned short ss; 49 unsigned short __ssh; 50 }; 51 52 #else /* __i386__ */ 53 54 struct pt_regs { 55 /* 56 * C ABI says these regs are callee-preserved. They aren't saved on kernel entry 57 * unless syscall needs a complete, fully filled "struct pt_regs". 58 */ 59 unsigned long r15; 60 unsigned long r14; 61 unsigned long r13; 62 unsigned long r12; 63 unsigned long bp; 64 unsigned long bx; 65 /* These regs are callee-clobbered. Always saved on kernel entry. */ 66 unsigned long r11; 67 unsigned long r10; 68 unsigned long r9; 69 unsigned long r8; 70 unsigned long ax; 71 unsigned long cx; 72 unsigned long dx; 73 unsigned long si; 74 unsigned long di; 75 /* 76 * On syscall entry, this is syscall#. On CPU exception, this is error code. 77 * On hw interrupt, it's IRQ number: 78 */ 79 unsigned long orig_ax; 80 /* Return frame for iretq */ 81 unsigned long ip; 82 unsigned long cs; 83 unsigned long flags; 84 unsigned long sp; 85 unsigned long ss; 86 /* top of stack page */ 87 }; 88 89 #endif /* !__i386__ */ 90 91 #ifdef CONFIG_PARAVIRT 92 #include <asm/paravirt_types.h> 93 #endif 94 95 struct cpuinfo_x86; 96 struct task_struct; 97 98 extern unsigned long profile_pc(struct pt_regs *regs); 99 #define profile_pc profile_pc 100 101 extern unsigned long 102 convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs); 103 extern void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, 104 int error_code, int si_code); 105 106 107 static inline unsigned long regs_return_value(struct pt_regs *regs) 108 { 109 return regs->ax; 110 } 111 112 /* 113 * user_mode(regs) determines whether a register set came from user 114 * mode. On x86_32, this is true if V8086 mode was enabled OR if the 115 * register set was from protected mode with RPL-3 CS value. This 116 * tricky test checks that with one comparison. 117 * 118 * On x86_64, vm86 mode is mercifully nonexistent, and we don't need 119 * the extra check. 120 */ 121 static inline int user_mode(struct pt_regs *regs) 122 { 123 #ifdef CONFIG_X86_32 124 return ((regs->cs & SEGMENT_RPL_MASK) | (regs->flags & X86_VM_MASK)) >= USER_RPL; 125 #else 126 return !!(regs->cs & 3); 127 #endif 128 } 129 130 static inline int v8086_mode(struct pt_regs *regs) 131 { 132 #ifdef CONFIG_X86_32 133 return (regs->flags & X86_VM_MASK); 134 #else 135 return 0; /* No V86 mode support in long mode */ 136 #endif 137 } 138 139 #ifdef CONFIG_X86_64 140 static inline bool user_64bit_mode(struct pt_regs *regs) 141 { 142 #ifndef CONFIG_PARAVIRT 143 /* 144 * On non-paravirt systems, this is the only long mode CPL 3 145 * selector. We do not allow long mode selectors in the LDT. 146 */ 147 return regs->cs == __USER_CS; 148 #else 149 /* Headers are too twisted for this to go in paravirt.h. */ 150 return regs->cs == __USER_CS || regs->cs == pv_info.extra_user_64bit_cs; 151 #endif 152 } 153 154 #define current_user_stack_pointer() current_pt_regs()->sp 155 #define compat_user_stack_pointer() current_pt_regs()->sp 156 #endif 157 158 #ifdef CONFIG_X86_32 159 extern unsigned long kernel_stack_pointer(struct pt_regs *regs); 160 #else 161 static inline unsigned long kernel_stack_pointer(struct pt_regs *regs) 162 { 163 return regs->sp; 164 } 165 #endif 166 167 #define GET_IP(regs) ((regs)->ip) 168 #define GET_FP(regs) ((regs)->bp) 169 #define GET_USP(regs) ((regs)->sp) 170 171 #include <asm-generic/ptrace.h> 172 173 /* Query offset/name of register from its name/offset */ 174 extern int regs_query_register_offset(const char *name); 175 extern const char *regs_query_register_name(unsigned int offset); 176 #define MAX_REG_OFFSET (offsetof(struct pt_regs, ss)) 177 178 /** 179 * regs_get_register() - get register value from its offset 180 * @regs: pt_regs from which register value is gotten. 181 * @offset: offset number of the register. 182 * 183 * regs_get_register returns the value of a register. The @offset is the 184 * offset of the register in struct pt_regs address which specified by @regs. 185 * If @offset is bigger than MAX_REG_OFFSET, this returns 0. 186 */ 187 static inline unsigned long regs_get_register(struct pt_regs *regs, 188 unsigned int offset) 189 { 190 if (unlikely(offset > MAX_REG_OFFSET)) 191 return 0; 192 #ifdef CONFIG_X86_32 193 /* 194 * Traps from the kernel do not save sp and ss. 195 * Use the helper function to retrieve sp. 196 */ 197 if (offset == offsetof(struct pt_regs, sp) && 198 regs->cs == __KERNEL_CS) 199 return kernel_stack_pointer(regs); 200 201 /* The selector fields are 16-bit. */ 202 if (offset == offsetof(struct pt_regs, cs) || 203 offset == offsetof(struct pt_regs, ss) || 204 offset == offsetof(struct pt_regs, ds) || 205 offset == offsetof(struct pt_regs, es) || 206 offset == offsetof(struct pt_regs, fs) || 207 offset == offsetof(struct pt_regs, gs)) { 208 return *(u16 *)((unsigned long)regs + offset); 209 210 } 211 #endif 212 return *(unsigned long *)((unsigned long)regs + offset); 213 } 214 215 /** 216 * regs_within_kernel_stack() - check the address in the stack 217 * @regs: pt_regs which contains kernel stack pointer. 218 * @addr: address which is checked. 219 * 220 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s). 221 * If @addr is within the kernel stack, it returns true. If not, returns false. 222 */ 223 static inline int regs_within_kernel_stack(struct pt_regs *regs, 224 unsigned long addr) 225 { 226 return ((addr & ~(THREAD_SIZE - 1)) == 227 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1))); 228 } 229 230 /** 231 * regs_get_kernel_stack_nth() - get Nth entry of the stack 232 * @regs: pt_regs which contains kernel stack pointer. 233 * @n: stack entry number. 234 * 235 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which 236 * is specified by @regs. If the @n th entry is NOT in the kernel stack, 237 * this returns 0. 238 */ 239 static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, 240 unsigned int n) 241 { 242 unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs); 243 addr += n; 244 if (regs_within_kernel_stack(regs, (unsigned long)addr)) 245 return *addr; 246 else 247 return 0; 248 } 249 250 #define arch_has_single_step() (1) 251 #ifdef CONFIG_X86_DEBUGCTLMSR 252 #define arch_has_block_step() (1) 253 #else 254 #define arch_has_block_step() (boot_cpu_data.x86 >= 6) 255 #endif 256 257 #define ARCH_HAS_USER_SINGLE_STEP_INFO 258 259 /* 260 * When hitting ptrace_stop(), we cannot return using SYSRET because 261 * that does not restore the full CPU state, only a minimal set. The 262 * ptracer can change arbitrary register values, which is usually okay 263 * because the usual ptrace stops run off the signal delivery path which 264 * forces IRET; however, ptrace_event() stops happen in arbitrary places 265 * in the kernel and don't force IRET path. 266 * 267 * So force IRET path after a ptrace stop. 268 */ 269 #define arch_ptrace_stop_needed(code, info) \ 270 ({ \ 271 force_iret(); \ 272 false; \ 273 }) 274 275 struct user_desc; 276 extern int do_get_thread_area(struct task_struct *p, int idx, 277 struct user_desc __user *info); 278 extern int do_set_thread_area(struct task_struct *p, int idx, 279 struct user_desc __user *info, int can_allocate); 280 281 #endif /* !__ASSEMBLY__ */ 282 #endif /* _ASM_X86_PTRACE_H */ 283